Stars, the Sun included, were born within clouds of dusty gas such as the Trifid Nebula in Sagittarius. Measuring some forty light years across, this nebula contains enough material to make many thousands of suns. Within it a number of young hot stars have already formed. These are more massive than the Sun, and hottest cause the gas in their immediate vicinity, which is mostly hydrogen, to emit its characteristic light, seen as red in colour pictures. Around the emission nebula the gas contains many dust grains which preferentially reflect the blue component of starlight, and to the north (top) of the nebula can be seen a bright star which illuminates part of the dust to create another region of reflection nebulosity. In some parts of the nebula there are so many dust grains that they hide the glowing gas, producing the three dark lanes which give the object its name, trifid meaning split into three parts.